The genetic control of the synthesis and function of macromolecular cell structures is studied by the three approaches; 1. Mutations in structural and regulatory genes controlling chlorophyll syntehesis in barley are used to analyze the role of the membrane protein protochlorophyll holochrome in the regulation of prophyrin synthesis and in the assembly of the photosynthetic membrane. Studies on organelle biogenesis include the indentification of genes coding for membrane proteins and lipids. 2. The organ specific biosynthesis of very long chain lipid molecules (fatty acids, hydrocarbons, diketones, alcohols, esters) is studied with the aid of mutations in 59 eceriferum genes affecting the epicuticular waxes in barley. 3. Precise pairing of homologous chromosomes in meiosis is a prerequisite for crossing-over, and is accomplished by the ribonucleproteins of the synaptinemal complex. Inversion and transposition heterozygotes in maize, haploids in barley and certain Drosophila strains are used to study the function of the synaptinemal complex in chromosome recognition. Isolation and chemical characterization of the synaptinemal complex from Allomyces and yeast is attempted with the purpose of identifying the components of the synaptinema complex as the product of specific recognition genes.